2 L12 71 en
9
5.4
Replacing the seat ring,
sizes DN 700–1400
Ensure that the valve is not pressurized.
Remove the valve from the pipeline. The valve must
be in a closed position during removal.
Follow the lifting methods shown in Section 3.
Remove the clamp ring (2) by untightening the
screws (27).
Remove the clamp ring, the old body seal (19) and
the seat ring (4). Change the seat ring if it is dam-
aged.
Clean all the seating surfaces of the body and clamp
ring. Check the surface of the seat ring.
Check also the condition of the disc. A damaged disc
must be changed (see Section 5.5).
Check the condition of the pin connection. Repair it
if necessary (see Section 5.5).
Mount a new, self-adhesive body seal (19) into the
body. The surface must be clean and free of grease.
Handle the ends of the seal according to Fig. 12.
Spray a thin layer of dry lubricant, e.g. Molykote 321R
or equivalent, into the seat groove, surfaces of the
clamp ring and seat ring.
Centre the seat ring (4) carefully into its groove and
turn the disc to maintain light contact with the seat.
Mount the clamp ring and tighten the screws (27)
lightly.
Turn the disc slightly open and pull it back to set the
seat into the proper position.
Tighten the screws (27) evenly. An unevenly tight-
ened flange may damage the seat ring.
Check the position between the seat ring and the
disc. The valve closes clockwise (see Fig. 13).
Mount the actuator into the valve. Adjust the closed
position limit and check the open position limit (see
Section 6.5).
5.5
Replacing the disc, shafts and
bearings, sizes DN 700–1400
5.5.1
Disassembling the valve
The pin connection of the disc must be opened by drilling for
changing the disc (3), shafts (11, 12) and bearings (15, 16).
Remove the valve from the pipeline and the actuator
from the valve.
Remove the clamp ring (2) and seat ring (4) accord-
ing to section 5.4.
Set the valve horizontally on a sturdy surface so that
the flat side of the disc lays against the surface, see
Fig. 14.
Drill the holes carefully to the centre of the pins (14).
Choose a drill 0.2–0.5 mm smaller than the diameter
of the pin.
Table 5
Tightening of live-loaded gland packing
Size
Spring set
dia
Thread
Compression (h
1
–h
2
) mm
Packing ring material
DN / NPS
mm
M, UNC
Gr
PTFE
PTFE
80 / 3
20
M8, 5/16
2.0
1.0
100 / 4
20
M8, 5/16
2.5
1.5
125 / 5
20
M8, 5/16
2.5
1.5
150 / 6
20
M8, 5/16
2.5
1.5
200 / 8
25
M10, 3/8
2.5
1.5
250 / 10
25
M10, 3/8
2.5
1.5
300 / 12
25
M10, 3/8
3.0
1.5
350 / 14
25
M10, 3/8
3.0
2.0
400 / 16
25
M10, 3/8
3.0
2.0
500 / 20
35.5
M14, 1/2
4.0
2.5
600 / 24
40
M18, 5/8
4.5
3.0
700 / 28
40
M18, 5/8
4.5
3.0
800 / 32
40
M18, 5/8
5.0
3.5
900 / 36
50
M20, 3/4
6.0
4.0
1000 / 40
50
M20, 3/4
6.0
4.0
1200 / 48
50
M20, 3/4
6.5
4.0
1400 / 56
50
M20, 3/4
6.5
5.0
CAUTION:
Do not dismantle the valve or remove it from the pipe-
line while the valve is pressurized!
Fig. 12
Mounting the body seal
Fig. 13
The contact line between the disc and seat
Fig. 14
Drilling the pins
open
close
Summary of Contents for L12 Series
Page 23: ...2 L12 71 en 23 ...
